With Thanksgiving holiday travel well underway, many have reached their destinations — but for everyone else, a storm tracking from the Rockies to the Midwest and Northeast into tomorrow will bring rain and snow, likely impacting flights and packed roads.

Just shy of 3 million people are expected to be screened by TSA today, and a record 71.7 million are expected travel by car over Thanksgiving — over 1 million more than last year.

The storm, already dropping snow over the Rockies Wednesday morning, is forecast to race east throughout today to the Midwest and Northeast through Thanksgiving.

It’ll bring rain that will intensify in the evening from St. Louis to Indianapolis and into Pittsburgh.

Airports in Denver, Kansas City, St. Louis are expected to see impacts of that weather today, NBC News’s Al Roker said on the “TODAY” show Wednesday, with slowdowns possible in Nashville, Dallas, Houston and Austin.

As of Wednesday morning, air travel was running relatively smoothly with nearly 500 delayed and 20 cancelled flights, according to FlightAware.

A ground delay at Newark Liberty International Airport in New Jersey, due to a shortage of air traffic controllers, lifted at 1 a.m. Wednesday.

For road travelers, I-80, I-64, I-75 will be impacted by rain Wednesday, and I-25 and I-70 with snow in the Rockies. 

Thanksgiving Day will bring a mess of rain for the I-95 corridor from Florida to Maine, and accumulating snow for the interior Northeast and northern New England.

Points north of the Hudson Valley in upstate New York and interior New England can expect 1 to 3 inches of wet snow, with localized totals of over 6 inches at highest mountain peaks.

The iconic Macy’s Thanksgiving Day Parade will go on rain or shine, as the Big Apple is forecast to see soaking rain with temperatures in the 40s. Winds are forecast to be less than 10 mph, which will allow balloons to fly. The parade’s beloved balloons cannot fly if maximum sustained winds hit 23 mph or greater or if gusts exceed 34 mph.

East Coast cities including Baltimore, Washington DC, New York, Hartford, and Boston can expect a cold rain, with rainfall totals between .50 to 1 inch. Road travel will be slick as far south as Virginia and Maryland, including through the I-95 corridor into Maine. 

By the overnight hours into Friday morning, travel will settle to mostly normal conditions as the system pushes out of the New England area.

However, a lake effect snow event starts up around the Great Lakes and will continue through Sunday.

Airport hubs to watch Thursday include Atlanta, Charlotte, Washington D.C., Philadelphia, NYC, Boston, Pittsburgh, and Buffalo.

On Sunday — typically the busiest travel day of Thanksgiving week as people return home from holiday trips — the cold will continue across swaths of the country, as well as lake effect snow around the Great Lakes and Northeast.

A total of 3 million people are predicted to pass through TSA on Sunday, nearing the record of 3.01 million that was set the Sunday following the Fourth of July holiday this year. 

Chicago and Detroit may see some problems at their airports on Sunday, but the East and West Coast look favorable for road and air travel.

All the while much of the northern Plains and upper Midwest will see bitter cold to close out the week, with temperatures forecast to be 10 to 20 degrees below average starting on Thanksgiving Day.

From Thursday to Sunday, Chicago will see highs in the 30s and 20s and lows in the teens, New York will see highs in the 40s and lows dip to around 28F, and D.C. will see highs in the 50s and 40s and lows in the 30s and high 20s. Minneapolis will see lows into the single digits over the weekend. 

As travelers take the skies to join loved ones, authorities are warning people who leave their cars in airport parking lots to take caution due to vehicle thefts.

Over 300 cars were stolen from the nation’s busiest airport, Hartsfield-Jackson Atlanta International Airport, this year — nearly three times as many as last year, Atlanta Police said.

“Suspects can program key fobs to vehicles and that has gotten us here where we are now,” Maj. Kelley Collier, the Atlanta Airport precinct commander said. This year, police are adding cameras, motorcycle patrols, and new fencing to curb crime across its 30,000 parking spaces. 

More than 50 vehicles were also stolen from Dallas Fort Worth International Airport this year, as police said a car theft ring targeting airports across multiple states was responsible. DFW Airport Police arrested the alleged ringleader last month.

A woman named Katy told NBC News she and her husband had went on a work trip and returned to Columbus International Airport to find their car was gone.

“In complete disbelief that we had parked attached to an airport and came out and our car was gone. We just assumed it was more safe and secure in that type of an environment,” she said. Police later found it abandoned and completely stripped. 

“I’m hoping that the airports will beef up their security so that we can travel and come back and have your car there,” she added.